Electrolytic fluid amplifier



United States Patent 1111 3,524,459

[72] Inventors Karl Gunnar Brunberg [56] References Cited 23 2 21, g H d I T UNITED STATES PATENTS 3:32 2,763,125 9/1956 Kadosch et a1. 137/81.5X [2 App. No. 702,009 3,071,154 1/1963 Carg1llet a1. 1. 137/815 3,122,062 2/1964 Spwak et a1. 137/81.5X [22] Filed Jan. 31, 1968 3,168,897 2/1965 Adams et a1 137/815 [45] Patented 2 3 263 695 7/1966 5 dd t 1 137/81 5 [73] Assignee Telefonaktiebolaget L M'Ericsson 3428066 2,1969 er 8 a 37/8 I Smckholm, Sweden err A Corp. of Sweden 1 Primary Examiner- M. Cary Nelson [32] Priority March 14,1967 Assistant Examiner William R. Cline [33] Sweden Attorney-Heine and Baxley 1 2697/27...

ABSTRACT: An electrolytic liquid amplifier has an inlet 1 [54] E g E g B 5 AMPLIFIER channel section, a constricted channel section and a bifurraw cated outlet channel section connected serially for passing an [52] 0.8. CI. 137/815 electrolyte. Electrodes in the constricted channel section [51] Int. Cl F15c 1/04 when energized cause the generation of a gas which controls [50] Field of Search 137/815; the direction of flow of the electrolyte to one of the branches 235/201; 204/ of the bifurcated channel section.

ELECTROLYTIC FLUID AMPLIFIER This invention pertains to fluid amplifiers and more particularly to such amplifiers using electrolytes.

Several methods are known in the prior art for controlling a liquid operated fluid amplifier by means of an electric current. The current can. for example actuate piezoelectric crystals, cause magnetostriction or electromagnetically operate a membrane, whereby the liquid flow is actuated mechanically. However these arrangements are bulky and are expensive.

' An object of the present invention is to provide an electrically controlled liquid operated fluid amplifier which is simple, requires little space and is cheaper to manufacture than the arrangements known in the prior art.

The fluid amplifier according to the invention is mainly characterized in that the liquid flowing through the amplifier is an electrolyte. Thus, when at least one electrode, arranged in the direction of the liquid flow in a constricted channel sec tion, receives an electric current an obstacle is caused, by gasification in the liquid, in the direction of the liquid flow on the wall part of the channel section adjacent to the electrode. Accordingly, the liquid flow will be deflected from that part of the wall and will form an acute angle with the centre axis in the constricted section. Hence, by arranging a number of electrodes in the constricted channel section around the centre axis and connecting a chosen electrode to a voltage source, the liquid flow can be directed from the centre axis to a direction determined by the chosen electrode.

The invention will be more particularly described below with reference to the accompanying drawing, in which FIG. 1 shows an embodiment of the invention and FIG. 2 shows a modification of the embodiment according to FIG. 1.

FIG. 1 shows an electrolytic fluid amplifier which can control the liquid flow in two alternative directions. The amplifier works in accordance with the following principle: An electrolyte E, which passes through a channel B having a constricted section F, can flow alternatively through two divergent channels C, and C Across the channel B there is a grid A, through which the electrolyte can flow. The grid is connected to the positive pole of a direct voltage source V so that it forms an anode. In the constricted section of the channel metal plates K, and K are arranged on partition walls of the channel situated opposite each other. These plates can be connected to the negative pole of the voltage source V to form cathodes. The plates are furthermore placed in such a way that they are situated on each side of the dividing plane of the divergent channels with their symmetry plane passing through the centre lines of the channels. The plates K, and K, can be alternatively connected to the negative pole of the voltage source V by means of a switch S so that alternatively one acts as a cathode in the flowing liquid while the other one is inactive. The connection of the voltage to either of the plates causes a gasification on that plate, which results in a further constriction of the constricted part of the channel in the direction from this plate. If, for instance, the plate K, is connected, the free through-flow section is obtained near the opposite wall which implies that the liquid flow from the channel B continues in the direction toward the divergent channel, C while the channel C, receives no liquid, not even after the electric current is disconnected as is generally known for fluid amplifiers. If it is desired to divert the liquid flow to the channel C, the switch 8 is adjusted to position lll, whereby the plate K is connected, the gasification resulting herefrom constricts the liquid flow toward the plate K, and the liquid flows through the channel C, while the flowing in the channel C ceases also after the current is disconnected. The fluid amplifier can thus be controlled by short electric pulses to the plates acting as electrodes.

In order to understand the efficiency of the invention an example will follow below. It is presumed that the electrolyte used is sulphuric acid and the developed gas is hydrogen.

According to Faradays electrolytic law the precipitated weight quantity of a substance is Furthermore the weight for hydrogen is 0.08869 kg/m at 0C and 1 bar. The following volume quantity is thus obtained 3g 3 96487 0.08869 -118mm that is by a current of l A (ampere) about 1 mm of gas is developed in 10 ms (milliseconds). This quantity of gas is large enough to actuate the fluid amplifier.

As is indicated by dashed lines in FIG. 1 it is possible to have one anode A and A respectively in each of the channels C, and C, respectively. The advantage of this arrangement is that, after changing of the liquid flow to either of the channels, the electric current need not be disconnected, but the current is automatically disconnected when the respective channel becomes free of liquid.

FIG. 2 shows another embodiment of an electrolytic fluid amplifier which can control the liquid flow in two alternative directions wherein the channels have the same design as in the arrangement according to FIG. 1. The difference is that the anodes have been placed in the immediate vicinity of the respective cathodes so that the voltage source is connected between one anode and one cathode on the side in the direction from which a change of the liquid flow is wanted. Thus, the gasification in the anode as well as in the cathode can be utilized, whereby the required flow is reduced.

The electrolyte in the channels C, and C, can be utilized in a way known in the prior art for actuating for example mechanical arrangements, but it is also possible to make the electrolyte directly close an electric circuit by arranging contact surfaces in the channels, through which the electrolyte is flowing. The electrolyte is then an electric conductor between the contact surfaces.

The invention is of course not limited to the described embodiments, thus an arbitrary number of channels can, for example, be arranged with a corresponding number of electrodes. One can for example conceive that the arrangement according to FIG. 1 in addition to the channels C, and C is provided with two further channels situated in a plane perpendicular to the plane of the channels C, and C In this case it is of course necessary that there be two further plates in addition to the plates K, and K so that one can connect one of the four plates to the negative pole of the voltage source by means of a suitable four-polar switch to become an active cathode. It is easily realized that the number of channels can be arbitrary and that the channels need not lie symmetrically distributed around a centre axis. The important thing is that the controlling of the through-flowing liquid is made by an electrolytic process in such a way that the cathode which is beyond the centre axis in relation to the channel to where the liquid flow is to be controlled in the same plane as goes through the centre axis and said channel, always connected to the negative pole of the voltage in order to control, by gasification, the liquid flow to the channel.

We claim:

1. An electrolytic fluid amplifier comprising a fluid conduit, said fluid conduit having an inlet channel section, a con stricted channel section and an outlet channel section, said constricted channel section being between said inlet and outlet channel sections, at least three electrodes within said fluid conduit, at least a first and second of said electrodes being disposed diametrically opposite each other in said constricted channel section, an electrolyte flowing through said conduit and in contact with at least two of said electrodes and means for applying a voltage across one of said first and second electrodes and another of said electrodes, and means for alternately connecting said voltage applying means to said first and second electrodes whereby a gas is generated about the one of said first and second electrodes connected to said voltage applying means to control the direction of flow of electrolyte in said outlet channel section.

2. The electrolytic fluid amplifier of Claim 1 wherein said outlet channel section has two branches symmetrically extending from said constricted channel section.

3. The electrolytic fluid amplifier of Claim 2 wherein said third electrode is disposed in said inlet channel section, said voltage applying means has one terminal connected to said third electrode and a second terminal, and said alternately connecting means comprises switching means for connecting the second terminal of said voltage applying means alternately to said first and second electrodes.

4. The electrolytic fluid amplifier of Claim 2 comprising at least two pairs of electrodes, the electrodes of each pair of electrodes being longitudinally displaced from each other in said constricted channel section and the pairs of electrodes being diametrically opposite each other, and said alternately connecting means connecting said voltage applying means alternately across the electrodes of said pairs of electrodes. 

